1. Field of Invention
The present invention relates generally to medical techniques directed toward remedying certain cases of sterility, particularly in humans, and more particularly to an apparatus facilitating artificial fertilization.
2. Status of Prior Art
By artificial fertilization is meant the technique which permits fertilization of the ovum or oocyte by the spermatozoon under conditions other than those provided by nature, for instance, under so-called "in vitro" conditions. An in-vitro fertilization technique entails the removal of the ovum follicle by means of a celioscope or echograph, allowing it to fertilize after capturing the spermatozoa, then allowing it to multiply in a physiological medium for a period close to 48 hours, and finally injecting the embryo thus formed into the uterus of the host mother, awaiting its implantation or nidation.
The above-described in-vitro operating steps are performed in a laboratory under conditions which are as close as possible to those of the natural medium of fertilization; that is to say, the peritoneal cavity.
This prior art method, although having the advantage of remedying certain cases of sterility, nevertheless has a rather limited rate of success, in the order of 10 to 25%. This low percentage of reliability appears to be due primarily to the difficulty of carrying out the last step; that is to say, the reimplanting of the fertilized egg or embryo. One of the reasons for this difficulty might be because of the closing of the neck of the uterus through which the egg implanatation cannula must be introduced three days after ovulation. This period of time results from the cumulative times of fertilization and multiplication in vitro. The penetration of the neck of the uterus which is closed during this post-ovulatory period, is frequently hermorrhagic, and it is known that blood is a factor which is unfavorable for the implanting of the egg.
There are other reasons that might explain the low rate of reliability. It is known that normally there is a negative pressure of a few millimeters of mercury as compared with atmospheric pressure in the peritoneal cavity. This reduction in pressure is normally transmitted into the uterine cavity through the fallopian tubes which are normally permeable. Numerous cases of sterility are due precisely to the closing of those tubes. In the above-mentioned method of in-vitro fertilization, the injection of liquid into the uterus would tend to produce an increase in pressure, and this could interfere with good contact between the egg and the mucous coat of the uterus.
Certain sterilities treated by in-vitro fertilization occur, however, despite permeable tubes. The above-noted interplay of pressures could then explain finding the embryo in a growth phase in the tubes. The egg in this case would have been aspirated under the effect of the positiveintra-uterine pressures towards the negative intra-abdominal or peritoneal pressures.